Malting grain

ABSTRACT

A process and apparatus for dehusking cereal grain by a dry mechanical method at a temperature not above about 105* F., and wherein the moisture content of the grain is above about 8 percent by weight in order to damage the grain so that substantial rootlet growth is prevented without substantially damaging the aleurone layer. The dehusked grain is subsequently malted and there are advantages compared with conventional malting of husked grain.

United States Patent Stowell et al. 1 Mar. 7, 1972 [54] MALTING GRAIN3,193,470 7/1965 Ma'cey et a1. ..195/71 Inventors: Keith ChrkmpherStowe", Newark; PM" 3,443,958 5/1969 Dennis et al. ..99/52 hg g lgo tt,Ne both FOREIGN PATENTS 0R APPLICATIONS o 11 an 8 786,973 11/1957 GreatBritain ..99/53 [73] Asslgnee: A.B.M. (Malting) Limited, Newark-omTrent, England OTHER PUBLICATIONS [22] Filed: July 15, 1968 Lake, .1.R., Harvesting Malting Barley, J. of Inst. of Brewpp 745 038 ing, Vol.72, p. 411, 1966 Primary Examiner-A. Louis Monacell 30 ForeignApplication p i it Data Assistant Examiner-Gary M. Nath Attorney--PaulH. Smolka July 21, 1967 Great Britain ..33,680/67 [57] ABSTRACT [52]U.S.Cl. ..99/52, 99/278, 195/71,

195/101 146/281 A process and apparatus for dehuskmg cereal grain by adry [51] Int. Cl. ..Cl2c l/00 mechanical memod at a temperature notabove about 581 Field or Search ..195/69, 70, 71, 130; 99/50, andwherein the mist 8131" is abve 8 52, 22 5, percent weight in order todamage the grain SO that Sllbstantial rootlet growth is preventedwithout substantially "n s damaging the aleurone layer. The dehuskedgrain is sub- [56] cued sequently malted and there are advantagescompared with UNITED STATES PATENTS conventional mailing of huskedgrain.

1 13,770 4/1871 Hofimann 146/281 20 Claims, 6 Drawing Figures Inventors:

KEITH CHRISTOPHER STOWELL and PETER MICHAEL HOW ETT A' TORNEYPATENTEDMAR (I972 515 47.473

SHEET 2 OF 2 Inventors:

KEITH CHRISTOPHER ST LL and PETER MI AEL H ETT BY Ax ATTORNEY MALTINGGRAIN The invention concerns improvements relating to the malting ofcereal grains, for example the malting of barley for use in brewing ordistilling.

By conventional procedure the selection of grain for malting has alwaysrequired that the husk of the barley is undamaged. A damaged huskusually indicated that mechanical damage to the grain had occurredduring harvesting or handling of the grain prior to purchase impairingthe malting quality of the grain.

Thus, undamaged husked grain has been used for malting. Briefly, inknown practice, the husked grain is steeped in water, then cast orfloored to germinate with the development and growth of the acrospireand possibly rootlets. The floored grain may be sprinkled with water.During germination the grain respires, and enzymes develop which convertthe proteins and starch of the grain into simpler substances which aremore soluble and/or diffusible. When germination has proceeded to arequired extent it is arrested by kilning the grain, which is thereafterscreened to remove the bulk of the rootlets. The malting loss, asmeasured by the loss in dry weight of material in processing barley intomalt, is represented by a steeping loss, the grain respiration loss, andthe screening loss.

During the steeping or germination period additives may be applied toregulate the malting process, in particular chemical additives may beincluded in the steep water and/or the flooring sprinkle water. Forexample, gibberellic acid, or sodium, potassium, calcium or otherbromate, or a combination of the acid and bromate may be applied inaccordance with any of U.K. Pat. Nos. 792,272, 993,521, 993,522,988,618, and 1,007,286.

We have now found that malted cereal grain can be prepared by removinghusk from the grain by a dry mechanical method damaging the grain sothat substantial rootlet growth is prevented without substantiallydamaging the aleurone layer thus allowing the dehusked grain to malt.

The invention provides a process of preparing malted cereal graincomprising the steps of removing husk from the grain by a dry mechanicalmethod damaging the grain so that substantial rootlet growth isprevented without substantially damaging the aleurone layer and maltingthe dehusked grain.

The expression dry in relation to the mechanical removal of husk is usedherein merely to exclude wet methods wherein the grain is slurrified fordehusking and does not limit the invention to the removal of husk fromcompletely dry grain.

The invention also provides malted cereal grain when prepared by such aprocess.

The invention also provides a process of producing wort wherein suchmalted grain is mashed.

The invention also provides wort wherein produced by such a process.

The invention also provides a product produced using such wort as a rawmaterial.

Preferably at least 95 percent by weight of the total husk of the grainis removed and preferably the temperature during dehusking does not riseabove about 90 F. but in some cases temperatures up to or a little above100 F. may be used but in any case it is preferred that the temperaturedoes not rise above about 105 F.

Although the husk is removed without substantially damaging the aleuronelayer of the grain, certain damage to the embryo occurs and damage toother areas may occur. The damage to the embryo is sufficient to preventsubstantial rootlet growth.

The invention goes contrary to known practice, but is believed toinclude advantages as follows:

1. More rapid uptake of moisture by the corn allowing a reduction insteeping time.

2. Rate of modification (as judged by the development of extract andsoluble protein) increases thus allowing reduction of the germinationperiod.

3. A reduction in the malting loss.

The overall advantage of the first two advantages mentioned above is tosignificantly reduce the processing time for the malting procedure, andthe third advantage improves the yield for the conversion of barley intomalt.

In addition, as the husk is removed prior to the malting process(normally 7-l0.percent of the weight of the barley) the throughput ofthe plant can be increased by this percentage, in addition to anyincreases arising from the reduction in the processing time.

A still further advantage arises from the fact that the husk of thegrain causes difiiculties which hinder the malting process (dormancy andwater sensitivity) and by removing the husk these problems are very muchreduced.

Preferably during the steeping and/or germination stage of the maltingprocess, chemical additive is employed to regulate the malting process.Additive may be included in the steep water and/or floor sprinkle waterat the germination stage, and may include gibberellic acid and/or abromate, basically as indicated above. However, another importantadvantage of the invention is that apparently the reaction of thedehusked grain to these chemical additives is more pronounced than thecomparatively docile reaction of normal husked grain and therefore bycomparison substantially less of an additive or combination of additivesis used to produce a desired effect.

Preferably not more than 0.25 parts per million by weight of gibberellicacid are used with respect to the dry weight of grain. Preferablybetween 50 and parts per million by weight of bromate (calculated aspotassium bromate) are used with respect to the dry weight of grain.

For example, in a typical known process of malting barley an additivetreatment comprises a water sprinkle with 0.25 parts per million ofgibberellic acid and 100 parts per million (calculated as potassiumbromate) of potassium, sodium or calcium bromate, with respect to thedry weight of barley.

With the invention comparable results can be obtained using only 50p.p.m. of the bromate, that is half normal, together with the sameamount of gibberellic acid.

Alternatively, comparable results can be obtained using a normal amountof additive, but more rapidly.

in a process of producing beer wherein malted grain is used as producedby the process described, husks removed from grain prior to malting are,for example, introduced at a stage subsequent to malting, for example byintroduction into the mash. The husks can have an advantageous effect inthe subsequent stages of the brewing process and on the resulting beer,and introduction into the mash facilitates subsequent filtrationthereof.

The invention also provides malting plant comprising dehusking means forremoving husk from cereal grain damaging the grain so that substantialrootlet growth is prevented without damaging the aleurone layer, andmeans for malting the dehusked grain.

The invention also provides wort production plant comprising suchmalting plant and mashing means adapted to receive malted grain from themalting means of said plant.

The invention is hereinafter described in further detail by way ofexample and not by way of limitation.

For malting barley, prior to malting the barley it is dehusked bymechanical means, without shattering the endosperm or causing to thegrain a degree of damage which would impair its function in malting. Thebarley for dehusking is normally taken as it comes, and no special stepsare taken to adjust its moisture content providing the moisture contentis between 8 and 16 percent by weight; below 8 percent excessiveshattering of grain may occur and above 16 percent the dehusking timemay be excessive. The dehusking action is distinct from that in theknown dehusking of barley or oats to improve the feed value, where theendosperm is shattered into grits which are only suitable for flaking orgrinding into a flour.

The dehusking can be effected by any suitable apparatus. One example ofsuch apparatus comprises a hemispherical bowl symmetrical about avertical axis with alloy propeller blading in the base comprising twoswept back generally curved blades, each of which presents a bluntleadingedge which is radiused and polished; theblading rotates aboutsaid axis at about 2,500 rpm. The blading is rotated by an electricmotor. With this action only the husk of the grain is removed. A smallpercentage of corns are broken (about 2 percent) but the aleurone layerof the corn is undamaged andthe embryo is not removed; broken corns areremoved before malting. The aleurone layer appears to have greatimportance in initiating the enzyme activity necessary for modification.The grain is very slightly damaged at the rootlet end and thisapparently has an advantage in relation to malting. The apparatusprovidesa consistent supply of dehusked barley. Grain size is immaterial whereas moisture content can significantly affect the degree ofdehusking and subsequent germination. Typical variations which may occurare shown in Table I; these results should only be considered asrelative to each other since a change in blading characteristic cansignificantly shift the balance in either direction.

Husk assessed as percent husk removed with respect to barley weight.

The dehusked'barley occupies about 90 percent of the volume of ordinarybarley, weight for weight. Thus effective barley storage increases byabout percent.

Handling of the dehusked material present no difi'iculty throughout theprocessing, and existing plant should cope adequately.

Preferably the grain is steeped to a moisture content between 1 and 2percent below the normal requirement for steeped grain which has not hadits husk removed. Preferably the steeped grain is sprinkled to amoisture content between 1 and 2 percent below the normal requirementfor steeped and sprinkled grain which has not had its husk removed.

Concerning steeping, Table II shows comparative rates of water uptake ofhusked and dehusked barley, for various steeping times at varioustemperatures. The water uptake is 50 given as percent of steeped grainweight.

The results shown in Table II indicate that the rate of uptake of wateris significantly increased by dehusking, and if steeping with no interimrest periods is adopted about a 25 percent 70 saving in time ispossible. However, it has been found that the introduction of asubstantial rest period during steeping permits a greater overall savingin time and thus an overall steep time of 30 hrs. raises the grainmoisture content to about 41 percent.

On flooring or casting, heavy sprinkling can be applied so that a finalmoisture level of about 43 percent is achieved. Raising the moisturecontent above this level does not substantially increase the rate ofmodification, as determined by the standard index of modification, butat a lower moisture percentage (40 percent) the germination period willbe slightly extended.

During flooring, modification proceeds with no or substantially nodevelopment of rootlet growth although a very small acrospire sometimesemerges. Consequently, the final volume of the grain is aboutthree-quarters of that normally found if equal weights are compared. Theanalytical development of the malt and physical breakdown proceed veryquickly between 24 hours and 48 hours after casting but during thisperiod the respiration rate does not appear to be greater than the peakobtained under normal conditions (500 mg. COJkg. dry wt./hr.).Therefore, no excessive demands are made on air supply and refrigerationcapacity in existing plant. The malting loss is about 2.5 percent; aboutone-third of this arises during steeping and the remainder must berespiration loss. There is a steep rise in the malting loss aftermodification has been completed and if the germination period is notcarefully regulated an over-modified malt is quickly obtained.

The process is extremely sensitive to chemical additive, as illustratedby reference to Table III, which shows results and trends of additivetreatment comprising in the sprinkle water applied during germinationgibberellic acid (GA) or a combination of GA plus a potassium, sodium orcalcium bromate (Br). Normal treatment comprises 0.25 p.p.rn. GA withrespect tobarley weight, here called NGA, and 100 ppm. Br with respectto barley weight, here called NBr. The Table shows the results aftervarious periods of flooring or 'germination, at (a) with a treatment ofNGA plus A: N Br (Le, 50

ppm. Br) at comparison air-on or flooring temperatures of TABLE III (a)Comparison air on temperatures F. and F. Additive treatment NGA plus NBr Time 24 hrs. 48 hrs. 60 hrs.

Temperature, F 60 70 60 70 60 70 Dry extract (lbs/qr.) 58. 4 84. 4 101.1 104. 1 108. 7 109. 2 Cold water extract, percent.. 5. 3 12. 6 15. 017.3 19. 9 23. 4 Permanently soluble nitrogen ereent 0. 19 0.31 0. 39 0.49 0. 52 0. 64 alting loss, percent 2. 4 4. 9

(b) Comparison additive treatments NGA and NGA. plus N Br Time 24 hrs.48 hrs. 72 hrs.

Additive NGA NGA NGA Dry extract (1bs./qr.) 70. 0 68. 5 106. 1 105. 4111. 3 110. 3 Cold water extract, percent. 6. 5 6. 2 17. 1 15. 5 20. 419. 1 Index of modification,

percent 21 18 50 26 51 31 NOTE.-D1'Y extract, cold water extract,permanently soluble nitrogen, and index of modification are all asdetermined by the re commended methods of The Institute of Brewing,London, England.

I NGA plus 'N Br.

Thus, for example, within the additive range NGA with no bromate to NGAwith normal bromate, the malt index of modification may vary after 72hours flooring from 51 down to 31, and a range of between 60 and 30 ispossible. Germination temperature is also influential, a rise of theair-on temperature from 60 F. to 70 F. in effect reducing the period forcomparable germination by 12 hours.

Preferred ranges of additives in the sprinkle water can involve usefulsaving as compared with the ranges normally used.

Concerning kilning, no substantial difference exists between the dryingrates of husked and the present dehusked malt. Compared to husked malt,the initial volume occupied by the dehusked malt is about 75 percent,but if kiln malts are compared as after the usual malt screening, thebulk densities are about equivalent. The dehusked malt tends to takecolor more easily on the kiln, but providing the Cold Water Extracts arekept within the normal range of brewing malt the color uptake can becontrolled. Moisture levels of under 3 percent might not be obtainedwhile keeping the malt color within the usual specification range sincethe high temperature necessary to reduce the malt moisture may causeexcessive color development.

Malt screening is unnecessary in the present process, as roots are notdeveloped during modification. Moreover, intensive screening mightremove the embryo altogether and its loss would cause in effect anincrease in malting loss and thus make the process less economic.However, under certain brewing circumstances removal of the embryo aftermalting and prior to brewing might be beneficial since it is known thatcertain fatty material which is extracted from the embryo can adverselyaffect the head retention in the beer.

The malted grain is mashed to produce a wort which for example in theproduction of beer or distilled spirits, such as whisky, is fermented bythe addition of yeast. Alternatively, for example the wort isconcentrated to a wort syrup.

The analysis and brewing properties of the dehusked malt will now beconsidered; all appropriate parameters are as determined by theRecommended Methods of the Institute of Brewing, London, England. Inview of the fact that the husks have been removed all the analyticalvalues of the malts are raised by 6-7 percent. Consequently, a normalale analysis for dehusked malt of ale-brewing quality would be in theorder of Dry Extract: 109 lbs., Cold Water Extract: 20 percent, Index ofModification: 40, whereas a typical lager malt would have a CongressAnalysis with a dry extract of 87 percent and Kolbach Index of 43percent. Obviously, I00 qrs. of dehusked malt would be equivalent inbrewing yield to about I06 qrs. of normal malt. There is a tendency forthe Diastatic Power of malts made by the present process to be slightlylower (10-20 percent) than normal but since they are so well modifiedthey convert during brewing in about half the time taken by a normal alemalt. The brewing worts are rich in a-amino nitrogen which is valuablefor yeast feeding during fermentation and also the wort pI-Is areslightly lower than normal. Thus, 100 percent utilization of this maltin mashing will produce a wort with a pH value 0.3 to 0.4 units lowerthan the value expected with a normal wort. Since this lowering of pH ofthe wort is often required by brewers it normally has to be artificiallyachieved by alternative treatments. The use of dehusked malt wouldapparently confer this benefit to the brewer without incurringadditional costs to the process.

We believe there are numerous advantages to be given to the beer qualitywhen using dehusked malt as described. Thus, due to a reduction in theanthocyanogen content of the beer the haze stability is improved and byadjusting the amount of husk used in the mash the beer flavor can bemodified to suit various circumstances. In other respects the beerproperties arising from the use of dehusked malt appear to be normal incomparison with the beers from malts made by the usual manufacturingprocess.

In a process of producing beer, the resultant malted grain may be mashedto produce wort, as a complete replacement for ordinary malted grain. Inthis case, husks removed from grain prior to malting are for examplereintroduced at a stage subsequent to malting, for example byintroduction into the mash, as indicated above. I-Iusks may bereintroduced in the same proportion to the dehusked grain after maltingas occurs with the original husked grain, or possibly in any desiredlesser or greater proportion. Preferably between 50 percent and I00percent by weight of husk removed is introduced into the mash, forexample substantially 100 percent.

Alternatively, the resultant malt may be mashed as an adjunct of normalmalted grain for example in the proportion of not more than 50 percent,e.g., between 25 and 50 percent with respect to the total weight ofmalted grain. Its virtue would be in its high extract yield, anabundance of yeast feeding properties and wort pH adjustment. Thesefactors would all be of considerable value to any brewer using highadjunct rates and thus this malt would be a good aid for providing abalanced wort.

The malt could be ground using the normal brewery milling equipmentalthough since the product is well modified an ad justment of the rollersettings might be necessary. Altematively the malt germination could bestopped after it has progressed for 48 hours which would then yield anormal modified product which may be cheaper than ordinary malt andwhich could be grounded by a normally set mill.

Also in a distillation process, the resultant malt may replace ordinarymalt in the mash tun either completely or partially by for example notmore than 50 percent e.g., between 25 and 50 percent with respect to thetotal weight of malted grain without causing filtration problems. Also,absorption of peat reek can be better with the dehusked malt incomparison with the normal product.

Reverting to the malting process, removal of the husk as describedfromdormant and water-sensitive barley has been found to break dormancy andreduce the degree of water sensitivity. Thus except when prolongedstorage is necessary the dehusking process may reduce the need andtherefore the expense of drying the conditioning barley. Furthermore,the socalled nonmalting varieties may make comparatively better malt bya dehusked process than by conventional techniques.

Economics of the present process are illustrated by the followingexample:

An 8 percent loss in barley weight due to removal of husk, and a 2percent loss in barley weight due to endosperm shattering, gives anoverall loss in barely weight 10 percent.

If barley is costed at qr. the weight loss will add 10/- to the cost ofl qr. of barley as ready for malting. However, the offal has a resalevalue of about8 per ton which reduces the overall loss to about 7/- qr.Consequently, the weight loss arising from the dehusking will add about7/- to the cost of l qr. (4 cwts.) of barley as ready for malting.

During the processing there is a saving in malting loss of between 3% to4 percent which is approximately equivalent to 7/- qr. Thus as anoverall balance the weight losses arising from dehusking are compensatedby the saving in malting loss.

Moreover, the husks may be reintroduced subsequent to malting asdescribed above.

We believe that the potential saving can be summarized as follows:

1. Increased throughput, for example of up to 50 percent, in

steeping and germination capacity.

2. Greater potential use of dormant and farm-dried barley withoutspecial drying and conditioning.

3. Cheaper and/or better malt products for the brewer.

The invention has been described above with reference to barley grain,but it is applicable to other cereal grain for malting such as wheat.

There now follows a description, to be read with reference to theaccompanying drawings, of brewing plant embodying the invention. Thisdescription, which is also illustrative of method aspects of theinvention, is given by way of example of the invention only and not byway of limitation thereof.

In the drawings:

FIG. 1 shows a diagrammatic view of the plant embodying the invention;

FIG. 2 shows a diagrammatic view of grain-dehusking apparatus;

FIG. 3 shows a diagrammatic view of parts of the apparatus, illustratingthe operation thereof;

FIG. 4 shows a plan view of a rotor of the apparatus;

FIG. 5 shows a side view corresponding to FIG. 4; and

FIG. 6 shows a section on the line VI-VI of FIG. 4.

The brewing plant (FIG. 1) embodying the invention comprisesgrain-dehusking apparatus 12, a separator 13, malting means 14, mashingmeans 16 and means 18 for converting mash into beer.

In the operation of the plant husk is removed from barley grain in theapparatus 12 and the husk is separated from the dehusked grain in theseparator 13; the grain then passes to the malting means 14, where it ismalted; the malted grain is then mashed with water and conventionaladjuncts in the mashing means 16; mash from the mashing means 16 thenpasses to the means 18 where it is converted into beer by conventionalprocessing. Each of the separator 13, malting means 14, mashing means 16and means 18, is known and forms no part of the present invention perse. I-Iusks separated in the separator 13 are, for example, added to themash in the mashing means 16; passage of the husks to the mashing means16 is indicated at 20. Any broken corns are removed from the dehuskedgrain before it is malted.

The dehusking apparatus 12 (FIGS. 2 and 3) comprises dehusking means 22for removing the husk of the barley grain, a weigher 24 for metering abatch comprising a required weight of barley to the dehusking means 22,a door assembly 26 adapted for use in removing the dehusked batch ofgrain from the dehusking means 22, a discharge hopper 29 and means (FIG.3) for so controlling the apparatus that when the apparatus is in use aplurality of cycles of operation are carried out consecutively in eachof which a weighed batch of grain is metered to the dehusking means 22,the batch is dehusked and the dehusked batch is removed through the doorassembly 26 and passes, via the hopper 29 to the separator 13.

The apparatus comprises a rectangular framework 27.

The weigher 24 comprises a weigh hopper 28 mounted for pivotal movementabout a horizontal pivot 30 secured in the framework 27 A weight 32 issecured on the hopper 28 and urges it anticlockwise about the pivot 30.The weigher 24 also comprises an inlet valve 34 communicating with abulk supply of barley (not shown); a valve member 36 of the valve 34 islinked to the hopper 28 by a link 38 (FIG. 3). The weigher alsocomprises an outlet door 40 which is mounted for pivotal movement abouta horizontal pivot 42 secured adjacent a lower, outlet, portion of thehopper 28. The dehusking means 22 comprises a bowl 44 having an invertedfrustoconical shell secured in the framework 27 with its axis verticaland adapted to contain barley grain to be dehusked. A rotor 46 ismounted on a vertical shaft assembly 48 for rotation about said verticalaxis in a lower portion of the bowl 44. The apparatus comprises anelectric motor 50 secured on the framework 27 and arranged to drive therotor 46 via a belt drive 52 and the shaft assembly 48, so that husk isremoved from the grain damaging the grain so that substantial rootletgrowth is prevented without damaging the aleurone layer.

The rotor 46 (FIGS. 4 to 6) comprises two 'sweptback generally curvedblades 41 which together present a generally S-shaped profile in planview. Each blade 41 presents a blunt leading edge 43 which is flame-cut,radiused and polished, and a trailing edge 45 which is flame-cut andrough ground. Each blade 41 comprises a horizontal brushed black platelower face 47 (FIG. 5) and a rough machined upper face 49 which slopesdownwardly from a central portion of the rotor 46. A bore 51 is providedin the central portion for securing the rotor 46 to the shaft assembly48.

A device (not shown) arranged to vary the speed of the rotor is alsoprovided. The speed may be varied according to the characteristics ofthe barley used.

The door assembly 26 comprises a door 54 which is mounted for pivotalmovement about a horizontal pivot 56 secured in the framework 27adjacent a lower, outlet, portion of the bowl '44.

The hopper 29 is secured in the framework 27.

The door 40 has a balance weight 58 (FIGS. 2 and 3) mounted thereon. Atoggle linkage 60 is connected to the door 40 and is arranged to openand close the door 40 as required. The toggle linkage 60 comprises alink 62 pivoted to the door 40 at 63 and also pivoted at 65 to a bellcrank member 64 which is pivoted to the hopper 60 by a horizontal pivot66. An arm 68 is pivoted to the hopper 28 by a horizontal pivot 70; thearm 68 is adapted to engage an arm 72 of the member 64. The arm 68 isconnected to a solenoid 74 which is arranged to move the arm 68 aboutits pivot 70. When the apparatus is in use and the hopper 28 contains abatch of the required weight, the solenoid 74 moves the arm 68anticlockwise about its pivot 70 and the arm 68, engaging the arm 72,moves the bellcrank member 64 clockwise about its pivot 66 to break thetoggle linkage 60 and allow the door 40 to open to deliver the batch ofgrain to the bowl 44. When the hopper 28 is empty the door 40 isreturned to its closed position by the action of the weight 58, thetoggle linkage being remade by the movement of the door 40 to hold thedoor 40 in its closed position.

The door 54 has a balance weight 76 mounted thereon. The door assembly26 comprises two spaced bellcranks 78 (only one of which is shown)arranged to open and close the door 54 as required. Each bellcrank 78 ispivoted in the framework 27 on a horizontal shaft 80. The bellcrank 78comprises an arm 82 on which is mounted a free roller which is adaptedto engage the door 54. The bellcrank 78 also comprises an arm 84 adaptedto engage a solenoid 86 arranged to move the bellcrank 78 about itsshaft 80. A balance weight 88 is also connected to the shaft between thetwo bell cranks 78. When the apparatus is in use and the rotor 46 hasbeen rotating for a required time, the solenoid 86 moves the bellcranks78 clockwise and the weight of barley in the bowl 44 causes the door 54to open to deliver the batch of barley to the hopper 27, the arm 84swinging away from the solenoid 86. When the bowl 44 is empty the door54 is returned to its closed position by the action of the weight 76,the weight 88 returning the bellcranks 78 to their position as shown inFIG. 3 to hold the door 54 in its closed position.

The control means of the dehusking apparatus (FIG. 3) comprises a timerdevice 90 of known type which forms no part of the present invention perse. The control means also comprises microswitches 92, 94, 96, each ofwhich is of known type and forms no part of the present invention perse.

In the cycle of operation of the apparatus the rotor 46 rotatescontinuously at a constant blade tip speed between and 400 ft./second,which corresponds approximately to between 1,500 and 5,000 r.p.m. with arotordiameter of 18 inches; initially the hopper 28 is empty. The emptyhopper 28 is urged by the weight 32 anticlockwise about its pivot 30 tomove the valve member 36 via the link 38 so that the valve 34 is openand barley grain enters the hopper 28 through the valve 34. As the grainenters the hopper 28 the hopper moves clockwise about the pivot 30 untilthe required weight is in the hopper 28, when the valve member 36 is ina position in which the valve 34 is closed. This movement of the hopper28 operates the microswitch 92 which operates the solenoid 74 to causeopening of the door 40 via breaking of the toggle linkage 60; theweighed batch of barley then falls into the bowl 44; the depth of theweighed batch is between I foot and 2 feet 6 inches. The door 40 inopening operates the microswitch 94 which initiates operation of thetimer 90.

After the required time, which is set on the timer 90, has elapsed thetimer 90 operates the solenoid 86 to cause opening of the door 54 viathe bellcranks 78; the dehusked barley then falls into the hopper 29.

While the barley is in the bowl 44 the hopper 28 again fills butv thesolenoid 74 does not operate again until the microswitch 96 is operatedby the arm 84 on return of the bellcranks 78 to their position as shownin FIG. 3, on closing of the door 54.

One or more of the following modifications can be made:

a. The bell cranks 78 are replaced by a direct-acting hook catchintegral with a magnetic release coil mounted in the framework 27.

b. Where auxiliary electric power supplies are not available thesolenoids and microswitches are replaced by interlocking mechanicallinkages.

c. The top faces of the rotor are horizontal.

it is believed that in the dehusking means 22 only the husk of thebarley is removed and the embryo is damaged so as to prevent substantialrootlet growth. A small percentage of corns are broken (about 2 percent)but the aleurone layer of the corn is substantially undamaged.

The following Table IV shows typical results obtained with the dehuskingapparatus described with reference to the drawings.

TABLE IV Barley moisture content: about by weight; Rotor diameter: 18inches; Germination: assessed as percent viable acrospires; Rotor tigspeed: 220 feet/second; Husk: assessed as percent husk removed witrespect to barley weight a. dehusking grain by a dry mechanical methodat a temperature not above about 105 F., and wherein the moisturecontent of the grain is above about 8 percent by weight so as to damagethe grain sufficiently to prevent substantial rootlet growth withoutsubstantially damaging the aleurone layer and b. malting the so dehuskedgrain.

2. A process according to claim 1 wherein the grain comprises barley.

3. A process according to claim 1 comprising the step of employing achemical additive to regulate the malting step.

4. A process according to claim 3 wherein the additive comprises agibberellic acid.

5. A process according to claim 3 wherein the additive comprises abromate.

6. A process according to claim 3 wherein the additive comprisesgibberellic acid and a bromate.

7. A process according to claim 4 wherein not more than 0.25 parts permillion by weight of gibberellic acid are used with respect to the dryweight of grain.

8. A process according to claim 7 wherein between 50 and 100 parts permillion by weight of bromate (calculated as potassium bromate) are usedwith respect to the dry weight of gram.

9. A process according to claim 1 wherein at least 95 percent by weightof the total husk of the grain is removed.

10. A process of producing wort comprising the steps of a. mashingmalted grain produced by a process according to claim 1 and Percent b.introducing into the so-produced mash husk removed from the grain by thedehusking.

ll. Malting plant comprising mechanical dehusking means for'removinghusk from cereal grain at a temperature not above about lO5 F. and at agrain moisture content above about 8 percent by weight which damages thegrain sufficiently to prevent substantial rootlet growth withoutsubstantially damaging the aleurone layer, and means for malting thedehusked grain.

l2. Wort production lant comprising a. a malting plant w lCh comprisesmechanical dehusking means for removing husk from cereal grain at atemperature not above about 105 F. and at a grain moisture content aboveabout 8 percent by weight which damages the grain sufiiciently toprevent substantial rootlet growth without substantially damaging thealeurone layer, and means for malting the dehusked grain,

mashing means for receiving malted grain from the said malting means andfor mashing said grain to produce wort,

0. means for separating husk from the dehusking means and d. means forintroducing said separated husk into the said mashing means.

13. Plant according to claim 11 wherein the dehusking means comprises achamber adapted to contain grain to be dehusked, rotatable blade meansin the chamber, and means for rotating the blade means.

14. Plant according to claim 13 wherein the blade means presents a bluntleading edge.

15. Plant according to claim 13 wherein the blade means comprises aplurality of swept-back generally curved blades, each of which presentsa blunt leading edge.

16. Plant according to claim 13 wherein said leading edge is radiusedand polished.

17. Plant according to claim 13 wherein the chamber comprises aninverted frustoconical shell with its axis upright and the blade meansis mounted in a lower portion of the chamber for rotation about saidaxis.

18. A process for preparing malted cereal grain comprising the steps ofa. removing husk from the grain by a dry mechanical method at atemperature not above about 105 F. and

wherein the moisture content of the grain is above about 8 percent byweight so as to damage the grain sufficiently to prevent substantialrootlet growth without substantially damaging the aleurone layer, thedry mechanical dehusking method comprising i. introducing the grain intoan inverted frustoconical shell with its axis upright, and

ii. rotating blade means in said shell about said axis, said blade meanscomprising a plurality of sweptback generally curved blades each ofwhich presents a blunt leading edge, at a blade tip speed between and400 feet/second; and

b. malting the dehusked grain.

19. A process according to claim 18, wherein the temperature duringdehusking does not rise above about F., and the moisture content of thegrain to be dehusked is between 8 and 16 percent by weight.

20. A process according to claim 18, wherein the grain is introducedinto the frustoconical shell until the depth of grain therein is between1 foot and 2 feet 6 inches.

2. A process according to claim 1 wherein the grain comprises barley. 3.A process according to claim 1 comprising the step of employing achemical additive to regulate the malting step.
 4. A process accordingto claim 3 wherein the additive comprises a gibberellic acid.
 5. Aprocess according to claim 3 wherein the additive comprises a bromate.6. A process according to claim 3 wherein the additive comprisesgibberellic acid and a bromate.
 7. A process according to claim 4wherein not more than 0.25 parts per million by weight of gibberellicacid are used with respect to the dry weight of grain.
 8. A processaccording to claim 7 wherein between 50 and 100 parts per million byweight of bromate (calculated as potassium bromate) are used withrespect to the dry weight of grain.
 9. A process according to claim 1wherein at least 95 percent by weight of the total husk of the grain isremoved.
 10. A process of producing wort comprising the steps of a.mashing malted grain produced by a process according to claim 1 and b.introducing into the so-produced mash husk removed from the grain by thedehusking.
 11. Malting plant comprising mechanical dehusking means forremoving husk from cereal grain at a temperature not above about 105* F.and at a grain moisture content above about 8 percent by weight whichdamages the grain sufficiently to prevent substantial rootlet growthwithout substantially damaging the aleurone layer, and means for maltingthe dehusked grain.
 12. Wort production plant comprising a. a maltingplant which comprises mechanical dehusking means for removing husk fromcereal grain at a temperature not above about 105* F. and at a grainmoisture content above about 8 percent by weight which damages the grainsufficiently to prevent substantial rootlet growth without substantiallydamaging the aleurone layer, and means for malting the dehusked grain,b. mashing means for receiving malted grain from the said malting meansand for mashing said grain to produce wort, c. means for separating huskfrom the dehusking means and d. means for introducing said separatedhusk into the said mashing means.
 13. Plant according to claim 11wherein the dehusking means comprises a chamber adapted to contain grainto be dehusked, rotatable blade means in the chamber, and means forrotating the blade means.
 14. Plant according to claim 13 wherein theblade means presents a blunt leading edge.
 15. Plant according to claim13 wherein the blade means comprises a plurality of swept-back generallycurved blades, each of which presents a blunt leading edge.
 16. Plantaccording to claim 13 wherein said leading edge is radiused andpolished.
 17. Plant according to claim 13 wherein the chamber comprisesan inverted frustoconical shell with its axis upright and the blademeans is mounted in a lower portion of the chamber for rotation aboutsaid axis.
 18. A process for preparing malted cereal grain comprisingthe steps of a. removing husk from the grain by a dry mechanical methodat a temperature not above about 105* F. and wherein the moisturecontent of the grain is above about 8 percent by weight so as to damagetHe grain sufficiently to prevent substantial rootlet growth withoutsubstantially damaging the aleurone layer, the dry mechanical dehuskingmethod comprising i. introducing the grain into an invertedfrustoconical shell with its axis upright, and ii. rotating blade meansin said shell about said axis, said blade means comprising a pluralityof sweptback generally curved blades each of which presents a bluntleading edge, at a blade tip speed between 100 and 400 feet/second; andb. malting the dehusked grain.
 19. A process according to claim 18,wherein the temperature during dehusking does not rise above about 105*F., and the moisture content of the grain to be dehusked is between 8and 16 percent by weight.
 20. A process according to claim 18, whereinthe grain is introduced into the frustoconical shell until the depth ofgrain therein is between 1 foot and 2 feet 6 inches.